Field of the Invention
One or more embodiments of the invention are related to drug infusion therapy systems. More particularly, but not by way of limitation, one or more embodiments of the invention enable a fail-safe drug infusion system, including a user interface controller (UIC) and at least one pump motor controller (PMC), with protocols that enable the PMC to operate therapy delivery for a limited amount of time in the event that UIC fails or the communication link between the UIC and the PMC is interrupted. Embodiments also include synchronization methods to synchronize the delivered drug status back to the UIC after the UIC reboots or after the communication link between the UIC and the PMC is restored. The PMC may apply intelligent fail-safe drug infusion therapy by temporarily displaying therapy information, for example information normally displayed on the UIC, while taking control of alarm signaling and providing minimal user control of the therapy until the UIC restores itself, the infusion completes normally, or the user stops the infusion. If the PMC becomes inoperable, the UIC may wait for the PMC to reboot, or attempt to switch drug infusion channels to provide robust drug infusion.
Description of the Related Art
Generally, current drug infusion systems do not synchronize information between multiple processors, or controllers, in order to enable one processor, or controller, to take over in a fail-safe mode and eventually recover from errors in the other processor or after restoring communications between processors. Some known systems utilize a secondary processor known as a “Safety Processor”, wherein such a safety processor may be used to keep the apparatus powered and to ensure delivery of a drug. These locally redundant systems generally switch to a redundant processor that may contain complex business logic inherent in the first processor, i.e., in the user interface code, which limits the robustness of the system since an error on the first processor may also occur on a second processor having the same or similar complex software code. In the event of a fault detected by either processor, including failure or loss of communication with the primary processor, the infusion may be stopped. Absent prompt caregiver attention and intervention, stopping some drug infusions may result in a delay in therapy that could lead to serious injury to a patient or even death.
In addition, current distributed systems appear to lack any suggestion of using a user interface controller (UIC), and a pump motor controller (PMC), that both maintain redundant, yet separate ability to manage alarm signals, user inputs, user displays, etc., to ensure continuous delivery of drugs in a robust manner. For example, typical systems lack any disclosure of limited backup capability in a microcontroller in the PMC, for example do not display infusion status on the PMC display that would normally be displayed on the UIC. Hence, these systems cannot possibly maintain fail-safe operation since no backup functionality exists for displaying infusion status, alarms or signals.
For example, U.S. Pat. No. 7,835,927 to Coffman et al., entitled “Medication Management System”, discloses a medical database carrier that may communicate information regarding medication delivery and other patient information between a control system in communication with a care-giving facility. As such, the system appears to lack any disclosure of fail-safe operation if a communication link between a first processor and a second processor is lost. For example, the system does not contemplate replacing the second processor's duties for the current delivery process, to continue to deliver a drug or medication, and to continue to power the system. The system also lacks any disclosure or suggestion of synchronizing delivery status after the communication link has been restored.
U.S. Patent Publication 20100200506 to Boehnlein et al., entitled “Flow Balancing and Synchronization System and Method, Especially for Citrate”, appears to disclose a renal failure therapy system including a blood pump, a citrate pump and a control unit configured to automatically control the blood pump and the citrate pump, for synchronization of flow rates. The system of Boehnlein et al., for example, discloses automatically adjusting for variations in flow rate, if one pump increases or decreases flow rate, using an external pump. In addition, the system appears to disclose a control processor in communication with a safety processor and two pumps, to monitor error conditions, receive status and parameter information from each of the pumps, ensuring safety limits are met. For example, if one pump is only inputting less ml/hour, an alarm is generated and the system automatically compensates for the loss by varying the pump rate of another pump. However, it appears as though the system lacks any disclosure of fail-safe operation if a communication link between a first processor and a second processor is lost. For example, the system does not contemplate replacing the second processor's duties for the current delivery process, to continue to deliver a drug or medication, and to continue to power the system. The system also lacks any disclosure or suggestion of synchronizing delivery statuses after the communication link has been restored.
In summary, there are no known fail-safe drug infusion therapy systems, including a first processor and a second processor, with protocols that enable the second processor to operate therapy delivery for a limited amount of time in the event that the communication link between the first processor and the second processor is interrupted that include synchronization methods to synchronize the second processor and the delivered drug status back to the first processor. In addition, there are no known fail-safe drug infusion therapy systems that display infusion progress and infusion statuses for example on a limited display connected to the PMC when the UIC is inoperable or when communication link is interrupted. For at least the limitations described above there is a need for a drug infusion system for synchronized fail-safe drug infusion therapy.